Di-heteroatom effects on aromatic character of triapentafulvalenes and their heavy analogues

Triapentafulvalenes is a completely conjugated unsaturated molecule. Many works have been done on triapentafulvalenes [1,2]. In this work, DFT calculations were carried out on molecular structure of triapentafulvalene and triapentafulvalenes-like containing heavy atoms (X = C, N, P, and As) by using 6-311++G** basis set of the GAUSSIAN 98 program. The aromatic character of that was investigated through magnetic criteria. Nuclear independent chemical shifts NICS (1.0) calculations clarified an aromatic character in both three and five member rings which was decreased in the order X = N > P > As > C in five-membered ring in 1X. However, the aromatic character in three-membered ring were decreased from X= As > P > N > C in 2X. The details and related discussions would be presented.